When Hawaii Air National Guard F-22 Raptors fly out of Joint Base Pearl Harbor-Hickam at $62,000 per hour on training missions, that effort is hampered by a multitude of inefficiencies, a recent government report said.

Fighters less sophisticated than the F-22 could be used as the “adversary” aircraft during training at a savings to taxpayers. However, the only fighters stationed in Hawaii are F-22s, so they must be used for all adversary training.

Compared with an F-22’s $62,000 an hour, a less sophisticated F-16 cost per flight hour in 2016 was $19,000, and $9,000 for a T-38, the report said.

To complete the adversary training, Hawaii-based F-22s were dedicated to flying against themselves at a reduced capability level, the U.S. Government Accountability Office report said.

A limited supply of Air Force adversary training aircraft also meant in 2017 that 55 percent of all F-22 sorties were devoted to adversary training, air-to-air combat — precious time that could have been spent on training for war air superiority, their main mission.

The Air Force categorizes adversary air sorties as useful only for maintaining basic flying proficiency, according to the GAO.

“An official representing the Hawaii unit indicated that the high percentage of (F-22) sorties dedicated to adversary air leads to wasteful training and declines in readiness against potential threats,” the GAO report said.

The July report found Hawaii to be at an even greater disadvantage because the low number of F-22s stationed here — 20 total — creates parts challenges, while storing them in open-air shelters in a high- humidity and salinity environment means the “low observable” coating — a thin film that makes the jets less visible to radar — needs to be reapplied more frequently in a time-consuming process.

Additionally, some of the Raptors have to be ready to fly a 24/7 Hawaii homeland defense “alert” mission, taking away training readiness when lesser aircraft are capable of flying the alert missions.

The GAO recommended a reassessment of the F-22 organization structure and the possibility of consolidating the fleet into larger squadrons. The Defense Department said the Air Force would study the F-22 home station structure and deployment practices.

In past years, with the Pentagon focused on low-technology adversaries in Iraq and Afghanistan, the F-22 was an advanced “fifth-generation” air superiority fighter looking for a mission.

But with competition heating up with China and Russia, the stealthy and highly capable Raptor is regaining attention at the “tip of the spear.”

The fighter is a linchpin in the Air Force’s ability to establish air superiority in a highly contested environment. Optimized for air-to-air combat, the F-22 is seen as complementary to the newer F-35 Joint Strike Fighter, which is more capable in air-to-ground missions.

The GAO maintains, however, that the Air Force hasn’t maximized the availability of its relatively small fleet of 186 F-22s due to maintenance challenges and unit organization.

“F-22 pilots are not meeting their minimum yearly training requirements for the air superiority missions,” GAO said.

The Defense Department said in a response that it is a “national military priority” to train F-22 pilots for near-peer competitors. According to the GAO, completing annual requirements for that mission requires pilots to train almost the entire year.

The Pentagon also directed the Air Force to pursue alternatives to using F-22s for alert missions. In Hawaii, F-22 pilots, maintainers and weapons crews are on call 24/7, ready to respond to civil or military threats. However, no other fighters are based here.

The Air Force already was planning to use private contractors for adversary training against F-22s — including in Hawaii.

That means retired attack aircraft such as the A-4 Skyhawk, which flew out of Kaneohe Bay in the 1960s and 1970s and is used by contractors including Florida- based Draken International, could be regularly flying in isle skies again, possibly in the 2019 time frame.

Pacific Air Forces, headquartered at Hickam, said it needed additional time to provide more details about the adversary air fielding plan.

The 186 F-22s are based at six locations around the United States, including Alaska and Hawaii. The Hawaii Air Guard “owns” its aircraft, while the active- duty Air Force also flies and maintains the jets as an “associate” unit.

The Air Force began its F-22 acquisition program in 1991 intending to get 648 aircraft. But schedule delays, cost increases and a changing threat environment pared that number to 381 and then the eventual 186, according to the GAO.

Reopening the production line would cost $50 billion to procure 194 additional F-22s. The idea was discarded with the Air Force funding improvement efforts for the existing jets, the report said.

Air Force squadrons traditionally have had 24 primary mission aircraft to optimize maintenance efficiency and combat power, according to GAO.

“F-22 squadron officials in Hawaii stated that increasing their squadron — the smallest in the fleet — by four additional aircraft would allow the squadron to generate 32 percent more sorties,” the report said.